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package Servlet1;

import java.io.IOException;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import javax.json.Json;
import javax.json.JsonObjectBuilder;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.core.MediaType;

/**
 *
 * @author Thet Paing Soe
 */
@WebServlet(name = "TimeServlet", urlPatterns = {"/time"})
public class TimeServlet extends HttpServlet {

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */
            out.println("<!DOCTYPE html>");
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet TimeServlet</title>");            
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>Servlet TimeServlet at " + request.getContextPath() + "</h1>");
            out.println("</body>");
            out.println("</html>");
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        TimeZone timezone;
        if(request.getParameterMap().containsKey("tz"))
            timezone=TimeZone.getTimeZone("tz");
        else
            timezone=TimeZone.getDefault();
        
        response.setContentType(MediaType.APPLICATION_JSON);
        response.setStatus(HttpServletResponse.SC_OK);
        
        DateFormat formatter=new SimpleDateFormat("dd MM yyyy HH:mm:ss z");
        formatter.setTimeZone(timezone);
        try(PrintWriter pw=response.getWriter()){
            JsonObjectBuilder builder=Json.createObjectBuilder();
            builder.add("time",formatter.format(new Date(System.currentTimeMillis())))
                    .add("local-time",formatter.getCalendar().getTime().toString())
                    .add("tz",timezone.getID())
                    .add("offset", timezone.getRawOffset());
            pw.println(builder.build().toString());
            pw.flush();
        }
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}
